The TAILORx Breast Cancer Trial

TAILORx seeks to incorporate a molecular profiling test into clinical decision making for breast cancer patients.

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The Trial Assigning IndividuaLized Options for Treatment (Rx), or TAILORx, is examining whether genes that are frequently associated with risk of recurrence for women with early-stage breast cancer can be used to assign patients to the most appropriate and effective treatment.

The majority of women with early-stage breast cancer are advised to receive chemotherapy in addition to radiation and hormonal therapy, yet research has not demonstrated that chemotherapy benefits all of them equally. TAILORx seeks to incorporate a molecular profiling test (a technique that examines many genes simultaneously) into clinical decision making, and thus spare women unnecessary treatment if chemotherapy is not likely to be of substantial benefit. TAILORx is one of the first trials to examine a methodology for personalizing cancer treatment.

The study has randomized more than 10,200 women with this type of breast cancer at 1,182 sites in the United States, Australia, Canada, Ireland, New Zealand, and Peru. Women recently diagnosed with estrogen-receptor and/or progesterone-receptor positive, Her2/neu-negative breast cancer that had not yet spread to the lymph nodes were eligible for the study. (See a summary of the TAILORx protocol for more information.)

The women were categorized into three recurrence risk groups depending on their score on the gene expression test. Women in the lowest-risk group were assigned to treatment with hormone therapy, women in the intermediate-risk group were randomly assigned to receive hormone therapy alone or hormone therapy plus adjuvant chemotherapy, and women in the highest-risk group were assigned to receive hormone therapy plus adjuvant chemotherapy.

In September 2015, results were reported from an analysis of the women in the lowest-risk group. The findings showed that at 5 years, rates of distant relapse-free survival were 99.3%, of invasive disease-free survival were 93.8%, and of overall survival were 98.0%. These results provide prospective evidence that the gene expression test identifies women with a low risk of recurrence who can be spared chemotherapy. (See the clinical trial result summary for more information.)

Results for women in the intermediate-risk group were presented at the 2018 American Society of Clinical Oncology annual meeting in Chicago and published in the New England Journal of Medicine on June 3. The findings showed that adjuvant hormone therapy alone worked as well as hormone therapy and chemotherapy together. After 9 years of follow-up, the rates of invasive disease-free survival were 83.3% for hormone therapy alone and 84.3% for hormone therapy and chemotherapy, and for overall survival, the rates were 93.9% and 93.8%, respectively. (See the press release for more information.)

TAILORx is sponsored by the National Cancer Institute (NCI), part of the National Institutes of Health (NIH), and is coordinated by the Eastern Cooperative Oncology Group (now the ECOG-ACRIN Cancer Research Group). All of the NCI-sponsored clinical trials groups that perform breast cancer research studies have collaborated in the trial’s development and are participating in this study.

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